Search for high energy cosmic muon neutrinos from variable gamma-ray sources and time calibration of the optical modules of the ANTARES telescope

Desde la primera evidencia de la existencia de los rayos cósmicos (c. 1910) y los primeros indicios de una nueva partícula fantasma más adelante llamada "neutrino" (c. 1920) ha pasado un siglo. Durante este tiempo, muchos experimentos e ideas teóricas han ampliado nuestro conocimiento sobre la física de partículas más fundamentales y los procesos astrofísicos más extremos del Universo. Una de estas ideas se propuso hace medio siglo: los telescopios de neutrinos, cuya se ha demostrado en la última década. Su objetivo es proporcionar una contribución fundamental a la comprensión de los procesos físicos alojados en los diferentes objetos astrofísicos a través de la detección de neutrinos de alta energía. Con el tiempo, pueden dar una respuesta al origen de los rayos cósmicos. Ha sido en los últimos años que han proporcionado la primera evidencia de la existencia de neutrinos cósmicos de alta energía. Este trabajo representa un esfuerzo en esta dirección. En esta tesis, múltiples análisis se han realizado a partir de datos del telescopio de neutrinos ANTARES con el fin de buscar correlaciones de neutrinos de alta energía con fuentes astrofísicas de rayos gamma conocidas. Los que se han estudiado en este trabajo son núcleos galácticos activos, binarias de rayos X y la nebulosa del Cangrejo. Además de la coincidencia en el espacio de neutrinos procedentes de estas fuentes, se ha utilizado la información de tiempo que se espera de sus emisiones de fotones a altas energías (rayos X y rayos gamma). Esto reduce sustancialmente el fondo y por lo tanto la cantidad de señal requerida para un descubrimiento en este análisis de fuentes puntuales. Adicionalmente, este trabajo también incluye la mejora del procedimiento de calibración del detector ANTARES. La estructura de este manuscrito es como sigue. En primer lugar, la física implicada y la justificación de las fuentes candidatas de neutrinos se introducen en el capítulo 1. A continuación, se presentan el principio de detección en la astronomía de neutrinos y la actualidad sobre los telescopios de neutrinos. En el capítulo 2, se describe el telescopio de neutrinos ANTARES. El rendimiento del detector y las simulaciones se presentan en el capítulo 3. El capítulo 4 está dedicado a la calibración temporal del detector. En particular, se describe el funcionamiento de los dispositivos de pulsos de luz controlados (balizas ópticas) y el análisis de sus datos. Su rendimiento a lo largo del tiempo ha sido evaluado y el éxito de la automatización de los procesos significa un activo valioso para esta tarea crucial en un telescopio de neutrinos, útil para detectores presentes y futuros. En el capítulo 5 la astronomía en energías de rayos X y superiores es descrita, junto a la introducción de los telescopios utilizados para obtener la información temporal de las emisiones de fotones de las fuentes candidatas analizadas aquí. Su caracterización y la definición de los períodos de gran emisión son también descritos. Estos análisis se basan en una técnica de cociente de máxima verosimilitud extendida, que se describe en detalle en el capítulo 6, junto con los procedimientos de optimización. Por último, la aplicación de esta técnica a las fuentes analizadas y los resultados derivados de ella se presentan en el capítulo 7, donde las conclusiones y límites a los flujos de neutrinos son presentados. El análisis de los datos obtenidos han proporcionado restricciones a los flujos de neutrions y también ha reforzado los resultados de IceCube con respecto a posibles fuentes de neutrinos cósmicos. Entre los posibles análisis que se pueden realizar, la que se presenta en este trabajo busca detectar la emisión de neutrinos de fuentes astrofísicas prometedoras conocidas mejorando el rendimiento del análisis al usar la correlación temporal esperada de la señal. De esta manera, la prueba de que procesos hadrónicas, que implicarían la producción de rayos cósmicos en ellos, podría encontrarse o restringir de otro modo.Since the first evidence of the existence of cosmic rays (c. 1910) and the first hints of a new ghost particle later on named "neutrino"' (c. 1920) has passed a century. During this time, many experiments and theoretical ideas have expanded our knowledge about the most fundamental particle physics and the most extreme astrophysical processes in the Universe. One of these ideas was proposed half a century ago: neutrino telescopes, the feasibility of which has been proven during the last decade. They aim to provide a crucial contribution to the understanding of the physical processes hosted in the many astrophysical objects by the detection of high energy neutrinos. Eventually, they may provide an answer to the origin of the cosmic rays. It has been during the last years that they provided the first evidence of the existence of high energy cosmic neutrinos. This work represents an effort in this direction. In this thesis, multiple analyses have been performed using data of the ANTARES neutrino telescope in order to look for correlations of high energy neutrinos with known gamma-ray astrophysical sources. The ones that have been studied in this work are Active Galactic Nuclei, X-Ray Binaries and the Crab Pulsar Wind Nebula. In addition to the coincidence in space of neutrinos coming from these sources, it has been used the time information expected from their photon emissions at high energies (X-rays and gamma-rays). This reduces substantially the background and therefore the amount of signal required for a discovery in these point source analyses. In parallel, this work also included the improvement of the time calibration procedure for the ANTARES detector. The structure of this manuscript is as follows. First, the physics involved and the justification of the neutrino candidate sources are introduced in chapter 1. Then, the detection principle of neutrino astronomy and the state of the art about neutrino telescopes are presented. In chapter 2, the ANTARES neutrino telescope is described. Performance and simulations are reported in chapter 3. Chapter 4 is devoted to the time calibration of the detector. In particular, the operation of the controlled pulse light devices (optical beacons) and the analysis of their data are described. Its performance along the time has been evaluated and the success of the automation of the processes means a valuable asset for this crucial task in a neutrino telescope, useful for present and future detectors. In chapter 5 the astronomy at X-ray energies and above are described, introducing the telescopes used to obtain the time information of the photon emissions of the candidate sources analysed here. Their characterisation and the definition of the flare periods are also covered. These analyses are based on an extended maximum likelihood ratio technique, which is described in detail in chapter 6 together with the optimisation procedures. Finally, the application of this technique to the analysed sources and the results derived from it are presented in chapter 7, where conclusions and limits on neutrino fluxes are discussed. The analysis of the obtained data have provided strong constrains and also reinforce of IceCube ones regarding possible cosmic neutrino sources. Among the possible analyses that can be performed, the one presented in this work seeks to detect neutrino emission from known promising astrophysical sources improving the analysis performance by the expected time-dependant bond of the signal. This way, the proof of hadronic processes that would link cosmic ray production with them would be find or constrained otherwise

The Neutrino Mediterranean Observatory Laser Beacon: Design and Qualification

This research was funded by the Ministerio de Ciencia e Innovación: Programa Estatal para Impulsar la Investigación Científico-Técnica y su Transferencia (refs. PID2021-124591NB-B-C41) (MCIU/FEDER); the Programa de Planes Complementarios I+D+I (refs. ASFAE/2022/023); Generalitat Valenciana: Prometeo (PROMETEO/2020/019); the Grisolía (ref. GRISOLIAP/2021/192) and GenT (refs. CIDEGENT/2018/034, /2020/049, /2021/23) programs; and the EU: MSC program (ref. 101025085), Spain.This paper encapsulates details of the NEMO laser beacon's design, offering a profound contribution to the field of the time calibration of underwater neutrino telescopes. The mechanical design of the laser beacon, which operates at a depth of 3500 m, is presented, together with the design of the antibiofouling system employed to endure the operational pressure and optimize the operational range, enhancing its functionality and enabling time calibration among multiple towers. A noteworthy innovation central to this development lies in the battery system. This configuration enhances the device's portability, a crucial aspect in underwater operations. The comprehensive design of the laser beacon, encompassing the container housing, the requisite battery system for operation, electronics, and an effective antibiofouling system, is described in this paper. Additionally, this paper presents the findings of the laser beacon's qualification process.Ministerio de Ciencia e Innovación: Programa Estatal para Impulsar la Investigación Científico-Técnica y su Transferencia PID2021-124591NB-B-C41Programa de Planes Complementarios I+D+I ASFAE/2022/023Center for Forestry Research & Experimentation (CIEF) PROMETEO/2020/019Grisolia GRISOLIAP/2021/192GenT CIDEGENT/2018/034, CIDEGENT/2020/049, CIDEGENT/2021/23EU: MSC program, Spain 10102508

Memory management unit for hardware-assisted dynamic relocation in on-board satellite systems

Satellite on-board systems spend their lives in hostile environments, where radiation can cause critical hardware failures. One of the most radiation-sensitive elements is memory. The so-called single event effects (SEEs) can corrupt or even irretrievably damage the cells that store the data and program instructions. When one of these cells is corrupted, the program must not use it again during execution. In order to avoid rebuilding and uploading the code, a memory management unit can be used to transparently relocate the program to an error-free memory region. This article presents the design and implementation of a memory management unit that allows the dynamic relocation of on-board software. This unit provides a hardware mechanism that allows the automatic relocation of sections of code or data at run-time, only requiring software intervention for initialization and configuration. The unit has been implemented on the LEON architecture, a reference for the European Space Agency (ESA) missions. The proposed solution has been validated using the boot and application software (ASW) of the instrument control unit of the Energetic Particle Detector of the Solar Orbiter Mission as a base. Processor synthesis on different FPGAs has shown resource usage and power consumption similar to that of a conventional memory management unit. The results vary between ± 1?15% in resource usage and ± 1?7% in power consumption, depending on the number of inputs assigned to the unit and the FPGA used. When comparing performance, both the proposed and conventional memory management units show the same results.Universidad de Alcal

Science with Neutrino Telescopes in Spain

[EN] The primary scientific goal of neutrino telescopes is the detection and study of cosmic neutrino signals. However, the range of physics topics that these instruments can tackle is exceedingly wide and diverse. Neutrinos coming from outside the Earth, in association with othermessengers, can contribute to clarify the question of the mechanisms that power the astrophysical accelerators which are known to exist from the observation of high-energy cosmic and gamma rays. Cosmic neutrinos can also be used to bring relevant information about the nature of dark matter, to study the intrinsic properties of neutrinos and to look for physics beyond the Standard Model. Likewise, atmospheric neutrinos can be used to study an ample variety of particle physics issues, such as neutrino oscillation phenomena, the determination of the neutrino mass ordering, non-standard neutrino interactions, neutrino decays and a diversity of other physics topics. In this article, we review a selected number of these topics, chosen on the basis of their scientific relevance and the involvement in their study of the Spanish physics community working in the KM3NeT and ANTARES neutrino telescopes.The authors gratefully acknowledge the funding support from the following Spanish programs: Ministerio de Ciencia, Innovacion, Investigacion y Universidades (MCIU): Programa Estatal de Generacion de Conocimiento (refs. PGC2018-096663-B-C41, -A-C42, -B-C43, -B-C44) (MCIU/FEDER); Generalitat Valenciana: Prometeo (PROMETEO/2020/019) and GenT (refs. CIDEGENT/2018/034, /2020/049, /2021/023); Junta de Andalucia (ref. A-FQM-053-UGR18).Hernández-Rey, JJ.; Ardid Ramírez, M.; Bou Cabo, M.; Calvo, D.; Díaz, AF.; Gozzini, SR.; Martínez Mora, JA.... (2022). Science with Neutrino Telescopes in Spain. Universe. 8(2):1-25. https://doi.org/10.3390/universe80200891258

Implementation and first results of the KM3NeT real-time core-collapse supernova neutrino search

The KM3NeT research infrastructure is unconstruction in the Mediterranean Sea. KM3NeT will study atmospheric and astrophysical neutrinos with two multi-purpose neutrino detectors, ARCA and ORCA, primarily aimed at GeV–PeV neutrinos. Thanks to the multi-photomultiplier tube design of the digital optical modules, KM3NeT is capable of detecting the neutrino burst from a Galactic or near-Galactic core-collapse supernova. This potential is already exploitable with the first detection units deployed in the sea. This paper describes the real-time implementation of the supernova neutrino search, operating on the two KM3NeT detectors since the first months of 2019. A quasi-online astronomy analysis is introduced to study the time profile of the detected neutrinos for especially significant events. The mechanism of generation and distribution of alerts, as well as the integration into the SNEWS and SNEWS 2.0 global alert systems, are described. The approach for the follow-up of external alerts with a search for a neutrino excess in the archival data is defined. Finally, an overview of the current detector capabilities and a report after the first two years of operation are given.Acknowledgements The authors acknowledge the financial support of the funding agencies: Agence Nationale de la Recherche (contract ANR-15-CE31-0020), Centre National de la Recherche Scientifique (CNRS), Commission Européenne (FEDER fund and Marie Curie Program), Institut Universitaire de France (IUF), LabEx UnivEarthS (ANR-10-LABX-0023 and ANR-18-IDEX-0001), Paris Île-de-France Region, France; Shota Rustaveli National Science Foundation of Georgia (SRNSFG, FR-18-1268), Georgia; Deutsche Forschungsgemeinschaft (DFG), Germany; The General Secretariat of Research and Technology (GSRT), Greece; Istituto Nazionale di Fisica Nucleare (INFN), Ministero dell’Università e della Ricerca (MIUR), PRIN 2017 program (Grant NAT-NET 2017W4HA7S) Italy; Ministry of Higher Education Scientific Research and Professional Training, ICTP through Grant AF-13, Morocco; Nederlandse organisatie voor Wetenschappelijk Onderzoek (NWO), the Netherlands; The National Science Centre, Poland (2015/18/E/ST2/00758); National Authority for Scientific Research (ANCS), Romania; Ministerio de Ciencia, Innovación, Investigación y Universidades (MCIU): Programa Estatal de Generación de Conocimiento (refs. PGC2018-096663-B-C41, -A-C42, -B-C43, -B-C44) (MCIU/FEDER), Generalitat Valenciana: Prometeo (PROMETEO/2020/019), Grisolía (ref. GRISOLIA/2018/119) and GenT (refs. CIDEGENT/2018/034, /2019/043, /2020/049) programs, Junta de Andalucía (ref. A-FQM-053-UGR18), La Caixa Foundation (ref. LCF/BQ/IN17/11620019), EU: MSC program (ref. 101025085), Spain

Responding to the challenges of Water and Global Warming: Environmental Hydrogeology and Global Change Research Group (HYGLO-Lab)

[EN] The current Global Warming of planet Earth is probably the most important geological phenomenon in the last 20,000 years of its history and for human race. This process is having nowadays notable effects on the climate, ecosystems and natural resources. Possibly the most important renewable geological resource is water. One of the most strategic phases of the water cycle is groundwater. Despite its low visibility, quantitatively (and qualitatively too) it is essential for life on Planet Earth. Foreseeable consequences on groundwater due to climate change and sea level rise will be very significant. Hydrogeology can provide answers to many of the questions that are beginning to be raised in relation to these impacts and their effects. Environmental hydrogeology is a way of understanding the set of disciplines mixed in Hydrogeology as a Science of Nature. The HYGLO-Lab Research Group of the IGME-CSIC National Center attempts, through its lines of research, with a double global and local component, to provide answers to some of these questions.Peer reviewe

Event reconstruction for KM3NeT/ORCA using convolutional neural networks

The KM3NeT research infrastructure is currently under construction at two locations in the Mediterranean Sea. The KM3NeT/ORCA water-Cherenkov neutrino detector off the French coast will instrument several megatons of seawater with photosensors. Its main objective is the determination of the neutrino mass ordering. This work aims at demonstrating the general applicability of deep convolutional neural networks to neutrino telescopes, using simulated datasets for the KM3NeT/ORCA detector as an example. To this end, the networks are employed to achieve reconstruction and classification tasks that constitute an alternative to the analysis pipeline presented for KM3NeT/ORCA in the KM3NeT Letter of Intent. They are used to infer event reconstruction estimates for the energy, the direction, and the interaction point of incident neutrinos. The spatial distribution of Cherenkov light generated by charged particles induced in neutrino interactions is classified as shower- or track-like, and the main background processes associated with the detection of atmospheric neutrinos are recognized. Performance comparisons to machine-learning classification and maximum-likelihood reconstruction algorithms previously developed for KM3NeT/ORCA are provided. It is shown that this application of deep convolutional neural networks to simulated datasets for a large-volume neutrino telescope yields competitive reconstruction results and performance improvements with respect to classical approaches

Event reconstruction for KM3NeT/ORCA using convolutional neural networks

The KM3NeT research infrastructure is currently under construction at two locations in the Mediterranean Sea. The KM3NeT/ORCA water-Cherenkov neutrino de tector off the French coast will instrument several megatons of seawater with photosensors. Its main objective is the determination of the neutrino mass ordering. This work aims at demonstrating the general applicability of deep convolutional neural networks to neutrino telescopes, using simulated datasets for the KM3NeT/ORCA detector as an example. To this end, the networks are employed to achieve reconstruction and classification tasks that constitute an alternative to the analysis pipeline presented for KM3NeT/ORCA in the KM3NeT Letter of Intent. They are used to infer event reconstruction estimates for the energy, the direction, and the interaction point of incident neutrinos. The spatial distribution of Cherenkov light generated by charged particles induced in neutrino interactions is classified as shower-or track-like, and the main background processes associated with the detection of atmospheric neutrinos are recognized. Performance comparisons to machine-learning classification and maximum-likelihood reconstruction algorithms previously developed for KM3NeT/ORCA are provided. It is shown that this application of deep convolutional neural networks to simulated datasets for a large-volume neutrino telescope yields competitive reconstruction results and performance improvements with respect to classical approaches